Pneumatic control system



Aug. 27, 1963 L.. M. HUBBY PNEUMATIC" CONTROL SYSTEM 7 Sheets-Sheet 1Filed Nov. 4, 1959 Aug. 27, 1963 M, HUBBY 3,101,614

PNEUMATIC CONTROL SYSTEM Filed Nov. 4, 1959 '7 Sheets-Sheet 2 A118 27,1963 1 M. HUBBY 3,101,614

PNEUMATIC CONTROL SYSTEM Filed Nov. 4, 1959 7 Sheets-Sheet 5 Aug. 27,1963 L. M. HUBBY 3,101,614

PNEUMATIC CONTROL SYSTEM Filed Nov. 4, 1959 7 Sheets-Sheet 4 Aug. 27,1963 1 M. HUBBY 3,101,514

PNEUMATIC CONTROL SYSTEM Filed Nov. 4, 1959 '7 sheets-sheet 5 Tlci.

L. M. HUBBY PNEUMATIC CONTROL SYSTEM '7 Sheets-Sheet 6 Aug. 27, 1963Filed Nov. 4, 1959 Allg' 27, 1953 L. M. HUBBY A 3,101,614

PNEUMATIC CONTROL SYSTEM Filed Nov. 4, 1959 7 Sheets-Shea?I 7 Tmp/4.

United States Patent AOliice 3,ltll,6l4 PNEUMATIC CDNTRL SYSTEM LaurenceM. Hubby, Bellaire, TeX., assigner to Texaco Inc., New York, NX., acorporation of Delaware Filed Nov. 4, 1959, Ser. No. 850,827 6 Claims.(Cl. 73-2240 'Ihis invention is concerned with automatic fluidmeasurement and delivery systems in general. More specifically, theinvention concerns a fluid handling system that is particular-lyadaptable to automatic custody transfer, in petroleum fluids.

In automatic custody transfer systems, it is important lthat thearrangements be set up in a 'fool-proof manner such that under anyconditions, eig. temporary power failure or the like, the system willcontinue to operate without :giving any terrors of indication lormeasurement of the quantity of fluid delivered.

Custody transfer systems may be classied into two :general categories;i.e. one, the measurements of lluid being delivered may be made bycontinuous ilcw metering, or two, the measurement may be made by anintermittent lilling and draining of a measured volume container ortank. This invention is concerned with the latter type of custodytransfer system, and is particularly benecial in the ability to providefor automatic delivery in an intermittent manner while insuring againstfalse counts of the number of quantities thus measured and delivered. Ina system of this sort it is important to avoid either the counting of avolume of fluid when such volume is not delivered, or on the other handa delivering of fluid that is in excess ci a volume count.

Heretofore the problem has been attacked in one way by providing amechanical connection, or tie, between the inlet valve and the drainvalve of a measuring vessel so that when the inlet valve is open thedrain valve will be closed and vice versa. Such approach to the problemis not practically feasible or readily adaptable to a system where themeasuring vessel is of a substantial size. Consequently, this inventionis especially adaptable to an intermittent volume measuring system wherethe vessel or tank that measures the volume delivered -is of asubstantial size, eig. on the yorder of one hundred barrels.

Theretore, it is an object o this invention to provide a system forautomatic custody transfer of a fluid, that involves the intermittentmeasuring of the quantity delivered by iilling and draining a known.volume receptacle. In addition, the system is particularly concernedwith a pneumatic control circuit for the necessary lill and drain valveoperation, and the like.

Another object of the invention is to provide an arrangement, in anintermittent measured quantity delivery system, for pumping the measuredil-uid to be delivered at a relatively steady rate, which is the averagerate of lluid delivery during the intermittent measurement of thepredetermined quantities thereof.

Briefly, the invention concerns a pneumatic control system for automaticcustody transfer of a lluid. The system comprises in combination a knownvolume measuring tank and a lill valve .for controlling the introductionof fluid to said measuring tank. The ysystem also comprises a drainvalve for controlling the removal of lluid rfrom said measuring tank,and pneumatic control means lfor actuating each of the lill and drainvalves. The system also comprises a pneumatic control circuit foractuating said pneumatic control means. F[The control circuit includespneumatic interlocks for preventing the actuation tof either said lillvalve or said drain valve, to open position so long as the other valveremains in its opened position.

Again briefly, another aspect of the invention may be described as beingconcerned with an automatic custody the invention.

2 transfer system which is one that has a principal supply source ofduid to be measured, as to the quantity thereof being delivered.Furthermore, such automatic custody transfer system is one that employsthe lfilling and draining of a known volume receptacle in order tomeasure the quantity delivered. rIlhus, the invention may be describedas comprising the following elements in combination: a pump fordelivering said duid from a sump after measurement thereof, a variablespeed engine for driving said pump at an average rate that is equal tothe average ow of said measured tluid, pressure responsive means foradjusting the speed of said engine, and means for introducing pressureto said last named means in n accordance with the head on said principalsupply source.

The foregoing and other lobjects and benefits of the invention will beappreciated more fully, in conjunction with a detailed description of apreferred embodiment of Such preferred embodiment is described below,and is illustrated in the drawings, in which:

FIG. l is a schematic diagram illustrating all of the elements of acomplete system according to the invention;

FIG. 2 is a front view, with the cover largely broken away, of a controlpanel cabinet that may be employed in connection with the system; p

FIG. 3 is an enlarged side view partly in cr-oss section of the upperportion of the control panel cabinet shown in FlG. 2, and taken alongthe lines 3--3 ofiFIG. 2 looking in the direction of the arrows;

FIG. 4 is a reduced front view of thecontrol panel cabinet, showing thecover thereon closed and illustrating the windows for observing a dumpcounter indicator as well as pressure and temperature recordingindications; i

FIG. 5 is an enlarged cross section View, illustrating a pneumaticsystem valve that is employed to cut oil delivery after a predeterminednumber of volume dumps have been made;

FIG. 6 is an enlarged elevation of a system detail, illustrating thedrain valve for the lFIG. l system, and including pneumatically actuatedcontrol means for such valv-e in addition to showing a pneumatic valvethat is included in the system; the pneumatic valve is actuated when thedrain valve reaches its closed position;

FIG. 7 is la Iturther enlarged system detail view, illustrating thepneumatic valve shown in FIG. 6 and providing more detail thereof; alsothis figure shows part of the pneumatically actuated valve actuatormechanism that is employed with the drain valve for opening and closingsame;

FIG. 8 shows an enlarged ydetail elevation, partly in cross section,indicating in general the internal structure of the drain valve shown inFIG. 6;

FIG. 9 is an enlarged cross sectional view of the inter-nal valveelements of the pneumatic valve shown in FIGS. 6 and 7; this view istaken along the lines 9 9 of FIG. 7.

FIG. l0 is an enlarged cross sectional view showing the internalstructure of ia pneumatic valve that is actuated by a fluid levelactuated float; this valve is the type employed wherever fluid levelcontrolled pneumatic valves are used in the '-FIG.1 system; v

FIG. l1l is an enlarged bottom view, partly in cross section, showingthe structure yof the double diaphragm four way valve illustrated inFIG. 3; v

FIG. l2 is au enlarged longitudinal cross section illustrating la relaytype pneumatic valve that is diaphragm actuated and that is employed inthe system for actuating the main control valve; y

FIG. 13 is an enlarged elevation partly broken away in cross section,illustrating a single diaphragm four way val-ve that is Aspring Ibiasedto one position thereof; there are two of these valves 'employed in thesystem and the satten Patented Aug. 27 1963.,

internal valve structure is like that of the FIG. 11, double diaphragmvalve;

` FIG. 14 is an enlarged elevation partly broken away in cross section,illustrating the elements ot a double diaphragm three way pneumaticvalve; there are two of these employed in the control system; and

IFIG. 15 is an enlarged detail elevation, largely in longitudinal crosssection, illustrating one of the manually actuated pneumatic controlvalves; this is a three W-ay valve, and there are two of them mounted onthe control panel at the central portion thereof.

Referring to FIG. l, the overall system 'and elements involved thereinwill be described lirst, as follows herebelow.

There is a measuring tank 2=1 that receives fluid to be measured from apredetermined source, such as a surge tank (not shown) as indicated bythe caption. Tank- 21 may lhave any predetermined volume for measuringthe quantity of` fluid therein, vand as indicated above, the systemaccording to this invention is particularly adapted to use with such ameasuring tank having `a volume on the order of one hundred barrels offluid. Of course, the invention is applicable to measuring vesselshavin-g other and different volumes', as desired.

The tank 2,1 is iilled by lluid that is introduced over a pipe 212y thatis connected to a `lill valve 23 'which in turn is connected (at theoutlet side thereof) to the tank 2l via another pipe 2.4. -It is pointedout that there is a three Way pneumatic valve 2-7 (schematicallyindicated in FIG. 1) that is mechanically connected to the lill valve 23in such a manner Vas to be `actuated from one position to another at theclosing 'of lill valve 23, as will appear more ful-ly below.

At the top of the tank 21, there is a float structure 30 that is subjectto actuation by the float thereof when the fluid level in tank 21reaches the location of the iioat. It will be observed that there is arelatively small diameter housing element 31 that contains the iioat ofthe float structure 30 so las to provide for maximum accuracy inconnection Iwith the volume of fluid in tank 21 when it has reached thelevel of the float. It Will `be observed that float structure 3Uactu-ates Ia three way pneu-matic valve 32. This is indicated by thedashed line connecting the symbol for valve 32, to the oat structure3l?.

At the bottom of the measuring tank 2l there is a drain pipe 35 whichconnects to a drain valve 36, which in turn may be substantially thesame kind of valve as the lill valve 23, i.e. a pneumatically actuatedvalve that is mechanically biased to its closed posi-tion in the absenceof pneumatic pressure applied thereto. Connected to the outlet side ofdrain valve 36, there is a pipe 37 that connects with a sump 3-8.

It Will be appreciated that Ithe sump 38 must have Sullicient volume tobe able to maintain the capacity thereor` always suilicient to providettor draining the measuring tank 21 While the pumping out from the sumpto a delivery point is carried out at any desired rate.

The fluid being delivered (and having the quantity thereof measured) iscarried away from the sump 38 via a pipe 41 that leads to a pump l2which in turn delivers the lluid via :a three way outlet valve 43 fordelivery to a customer via convenient means, eJg. a pipe line asindicated.

It will be observed that there `are additional elements employed inyconnection with the delivery of the liuid trom sump tank 38 to thecustomer. These elements include an engine 46 that drives the pump 42.The engine is preferably a gasoline motor, or other type of internalcombustion engine. The speed of engine d6 is controlled by positioningthe throttle thereof in accordance with the head pressure that exists onthe surge tank which delivers the fluid to the measuring tank Z1.

The latter elements act to control delivery of the fluid and this isaccomplished by employing the schematically illustrated elementsincluding a diaphragm 47 that is connected to receive pressure thereinin accordance with the fluid Ihead on the surge tank (las indicated bythe caption). Diaphragm 47 is mechanically connected via any Afeasiblelinkage (such as that schematically indicated) to position a throttlelever 48 on the engine 46, by means of la lever arm 49. Arm 49 ispivoted at 'a pivot point 50, and is move-d in accordance with thepressure on the diaphragm 47 by means of a connecting link 51. Thethrottle lever 48' is urged toward the throttle lclosing position by aspring 54 that has one end thereof anchored to some Iframe, Ior fix-edreference point. It will be observed that if the pressure ion the'diaphragm 47 fails, the spring 54 Will take over and move the throttlelever 48 to its idle position that is indicated by the arrow.

It is pointed outthat lwith the indicated arrangement, the engine 46will be maintained at a speed that is dependent upon the head pressureexisting in the surge tank which supplies measuring tank 21. By thisarrangement, the amount of fluid that is pumped out for delivery to thepipe line by means of pump 42, is varied in accordance with the head orlevel of fluid in the surge tank. In this manner the average tlow offluid being delivered will tend to be maintained at a rate which isequal to the average amount of iiuid `bein-g intermittently deliveredfrom the measuring tank 2.1 each time that it is lilled. The result ofsuch ian arrangement is beneficial in that the power required forpumping fluid in delivering same, is held to a minimum since no excessof iluid is being delivered, over the quantity required in accordancewith that being measured in an intermittent manner. Thus, it becomesquite feasible to arrange the system for a substantially continuousdelivery of la fluid at a predetermined most desired rate, with theminimum of power required in so delivering the fluid.

There are some auxiliary` elements involved in the arrangement forpumping the fluid as it is delivered. These include a float controlledValve housing 57. This contains a three Way pneumatic valve asschematically indicated by a symbol 58, shown in connection with apneumatic control circuit. Such control circuit is for actuating thedelivery valve 43', as Well as an idle override control element '519.The idle override element 59 is controlled or actuated by a pneumaticdiaphragm 60 that is connected to the three way pneumatic valve 5S, forreceiving pneumatic pressure when the level of fluid in the sump 318goes below a predetermined level as set by the location of the valvehousing 57. There is a pneumatic actuator 63 for the valve 43. Thisactuator is connected in parallel with diaphragm 60 so that at thepredetermined fluid level, valve 43 will be closed to the line and willconnect the output of pump 412 to a bypass pipe d4. At the same timeIthe element 59 will act to move the throttle lever 4d of the engine 46to its idle position.

Returning to the measuring tank and its operation, it Will be furtherobserved that there is` a float housing structure `67 that contains thelloat structure and connecting elements for actuating a pneumatic threeWay valve 68. Actnation of the valve `618` is used to provide a controlfunction When the measuring tank Z1 is at its empty condition, i.e. thelevel of the fluid in the drain pipe 35 goes below housing 67.

As indicated in greater detail in the FIG. 6 illustration, it will benoted that the float structure within housing 67 is connected to thedrain pipe 35 at 'an angle thereto for avoiding any effect of turbulenceduring the fluid llow as it is drained.

The control system acts to automatically measure the quantity of luid byiilling tank 21 and emptying same, while taking a count of the number ofdum-ps, or time that is carried out. The control system is pneumatic innature and includes connections to each of a pneumatic actuation element71 for the fill valve 23, land a similar pneumatic actuator 72 for thedrain valve 36. Pneumatic control of these actuators acts toautomatically maintain the lling and draining of the measuring tank 21in a continuous manner, while at the same time the counting of thenumber of times that the tank is drained is carried out by a counterconnection that will appear more specically below.

The pneumatic control system is schematically illustrated in FIG. 1 bymeans of :a single line diagram that includes the following elements, inaddition to those already indicated. There is a pneumatic supplypressure line 75 that delivers pneumatic fluid under pressure to aregulator 76, which has the output side thereof connected via apneumatic line 77 to three parallel pneumatic. paths. These pathsinclude a pneumatic line Si)l and a line S1, as well as a line 82. Inaddition there is a pneumatic line 83 that is connected to a three |waypneumatic valve (relay type) which is shown enclosed in a 4dashed linebox 86. There is also a pneumatic line 8.7 that (like line 83) isydirectly connected to the common line 77 by means of line 8l. Thus, aswill appear more fully below, the three parallel pneumatic circuitsinclude the circuit of pneumatic line 8l), the circuit of pneumatic lineg2 and also the circuit that includes lines Sl, 33 and 'I'he pneumaticlines 8-2, '81. and 87 are actually joined togethervin a singlepneumatic path, by reason of the structure of a control valve 9i) thatis shown schematically and that includes the elements enclosed in fthedashed line rectangle (90). These Aelements include a drain diaphragm911 and a iill `diaphragmy 92, in addition to a four Iway pneumaticvalve structure. The tour way valve is illustrated as two three wayvalves 93- Iand 94 respectively. T his is done by way of convenience inconnection with the pneumatic circuit diagram showing of FIG. 1.

The upper three way valve 93 is designated as the fill control valve(indicated lby the letter F), while the lower three way valve 94 isdesignated as the drain control Valve (D).

There is a mechanical counter 97 that is connected to the structure ofcontrol valve 901, so as to count the number of times that control valve9d moves to its drain control position. Connected mechanically tocounter 97, in turn, there is a pneumatic control valve ithat may be setfor actuation by the counter 97 only after a predetermined number ofdumps of the measuring tank 21 have been made, so that the `delivery ofHuid may be automatically stopped at a given quantity (after thepredetermined number of dumps) as desired.

The control valve 90 is actuated to either its drain, or till, controlposition by means of pneumatic pressure supplied to the drain and tilldiaphragms 91 and 912 respectively. This pneumatic fluid pressure iscontrolled by the use of two (relay type) diaphnagm actuated pneumaticvalves 86 and 99. Thus valves 86 and 99 are each three way valves thatare actuated by introducing pneumatic fluid under pressure to thediaphragm thereof.

In the absence of such pneumatic pressure, the valve in each case isspring biased to the opposite state. These are arranged so that thethree way valve (of each) is actuated by the `diaphragm actuator thereof(when pneumatic pressure is applied thereto) to connect the inputpneumatic line, eig. line 83 of the valve 86; to the output linetherefrom, eig. the line which leads to the `drain control diaphragm 91of the pneumatic control valve 9d. On the other hand when no pneumaticiluid pressure is applied (to the Idiaphragm of valve' `86) then saspring bias arrangement moves the valves to its other position whichclosesthe pneumatic line (eg. line 83) while it connects the output line(eg. that leading from diaphrag 91) to the atmosphere to vent same.

` In order to provide a predetermined time delay before the actuation ofrelay valves 86 and 99, there is a pneumatic volume tank 102 and 103connected respectively to the pneumatic lines leading to the diaphragmactuators of the relay valves 86 and 99.

The rest of the pneumatic. control system includes 6 pneumatic supplylines as illustrated, in addition to apair of manual three way pneumaticvalves 106 and 107 that are connected into the system so as toarrest theautomatic drain and ill operation of measuring tank Z1, either in thefull or in the empty condition, as desired.

' The control system also includes a pair of double diaphragm actuated,three way pneumatic valves 1 10 and ill (enclosed by dashed line boxesin FIG. l). These valves operate in the control system to insure properoperation thereof, as will appear. There are also a pair of singlediaphragm actuated, spring biased, four way valves 114 and 1115 (alsoenclosed by dashed line boxes in FIG. 1)'. These are illustrated as two`individual three way valves, for convenience in showing the pneumaticcircuits, as was the case for the control valve 90.

There is a three way pneumatic valve 118, that is mechanically connectedto the measuring tanks drain valve 36, for actuation thereby rwhen thedrain valve is in its closed position.

Operation 0f FIG. 1

It is pointed out that the schematic system showing of FIG. 1 indicatesthe elements required and the pneumatic interconnections therebetween,in order to provide for the automatic measuring operations as desired.It will be understood that each of the various elements of the systemmay be for the most part, commercial items that yare conventional andreadily available. Thus, a description of the system operation will beprovided, without indicating the detailed structure of the elementsemployed; and then particular elements that may be used in the systemwill be described sufliciently to clarify and provide a workingillustration of elements that may be employed for carrying out thesystem operation.

The system will operate automatically, to continuously carry out theprocess of lilling and draining measuring tank 211., while providing acount of the number of times that the tank 21 is emptied, or dumped.However, there is provision for manually overriding the automaticoperation, it desired, so as to stop the process with the measuring tank2'1 either in the full condition or in the kempty condition, as desired.In addition, there is provided a control from the counter element so asto stop the process of filling and dumping measuring tank 21automatically after a predetermined number of dumps has been made.

As indicated above, the pneumatic control system is illustratedschematically by a line diagram in FIG. 1; which illustrates thepneumatic pipes and other pneumatic circuit connections, and employsdots where such pipes are interconnected.

The operation of the system will be made clear by following the controlsteps, and the condition of the various pneumatic valves in the system,as a complete cycle of filling and dumping of the measuring tank 21 iscarried out. Thus, commencing with the operation as measuring tank Z1 isin the process of being iilled (by introduction of the Huid via pipe 22and through the lill valve 23 to pipe 24 that leads into the measuringtank 21), it will be observed that the pneumatic control system isactuated by pneumatic iluid under pressure as introduced over thepneumatic line 75 and via the regulator 76y which is included in orderto maintain a relatively constant pneumatic pressure on the controlsystem. Consequently, pneumatic pressure is supplied continuously overthe line 77 to the common connection point for pneumatic lines 80, 81,S2. In addition, pressure is supplied continuously over lines 83 and 87that are connected in common to line 81. The distribution of thepneumatic pressure over the various pneumatic circuits, is thencontrolled by the various pneumatic control valves and other elements,to determine the action in connection with illing and draining of themeasuring tank 21.v Thus, pneumatic control valve is a primarydetermining element as to the actuation of the various controls to setup 7 and initiatethe opening and lclosing of the hll and drain valves,as desired.

In accordance with the above, it will be assumed that the measuring tank21 is lling by reason of till valve 23' being pneumatically actuated toits open position, i.e. by having pneumatic pressure applied to thepneumatic actuating element 71 thereof. This `application of pneumaticpressure is provided by reason of the fact that the control valve 90stands in its lill position. In other words, the three way valve 93 isOpen for allowing pneumatic pressure to pass therethrough; while theother three way valve 94 is closed so that pneumatic pressure from line'82 is shut ofI, and the pneumatic pressure that existed on a pneumaticline 125 is vented to the atmosphere at three way valve 94.

The pneumatic pressure is therefore carried through three way valve 93from pneumatic line 87 Via another pneumatic line 126 to a commonconnecting point 127. From point 127 the pneumatic pressure is carriedover a pneumatic line `128 to the input side of the three way valve 32,that stands in its open position since the fluid level in measuring tank21 has not yet reached the float structure 30 (in housing 311) thatcontrols the three way valve 32. Since the valve 32 is open, thepneumatic pressure is carried through the valve over another pneumaticline 131 to the diaphragm of the pneumatic actuator for the singlediaphragm Valve 114. Valve 114 is spring biased to a position such thata three way valve 132 thereof, is normally open While another three wayvalve 133 thereof is normally closed. However, under the presentlydescribed assumed conditions, the three way valve 132 will be closed andthe other three wayv valve 133 will be opened because the diaphragm ofthe valve 114 has pneumatic pressure applied thereto. Consequently,pneumatic fluid ow due to pressure existing in a line 136, is cut off atthe three way valve 132, while the pneumatic pressure on anotherpneumatic line 137 (connected to common point 127) is transmittedthrough the valve v133 to another pneumatic line 138 that leads to thethree Way valve 98 which is actuated under control of the counter 97, aswas indicated above and will be more fully described below in connectionwith the details of the system elements.

Assuming the predetermined number of dumps has not been reached at thispoint, the three Way valve 98 (controlled from counter 97) `will be openand will `allow pneumatic iluid pressure to pass directly -to the manualvalve 107. Manual valve 107 will be set in its open position, so thatpneumatic pressure will pass through the valve 107 also; From here itpasses directly to an auxiliary three way valve 141, and then on via apneumatic line 142 to pneumatic lines 143 and 144 in common. Thepressure in line 144 is transmitted via another pneumatic line 147, tothe three Way valve 118 that stands in 'its `open position under theassumed conditions because the drain valve 36 is closed. Then, pressureis transmitted on over another pneumatic line 148 to the diaphragm(pneumatic actuating element) 71, of the ll valve 23. This will causethe element 71 to be actuated so that the ll Valve 23 is held in itsopen position.

The pneumatic control system will remain in the above described stateduring the period when measuring tank 21 is being lilled, and then itwill automatically switch over to drain the measuring tank 21 after iillv-alve 23 has been closed. This will take place by reason of the actionthatis initiated by the float-actuated, three Way Valve 32, when thetank 21 is full. Thus, it is pointed out that when the oat structure 30is affected by the iluid level in the measuring tank 21, it will shiftthe three Way valve 32 from its open condition to its closed condition.Consequently, pneumatic iluid flow due to pressure in pneumatic line128, will be cut olf at the valve 32; While the other pneumatic line 131(that connects to the output side of the valve 32) will be vented to theatmosphere by the valve 32. Tlhis venting of pneumatic pressure on line131releases the diaphragm vactuator of the valve 114 and allows thespring bias thereof to shift the three way valves 132 and 133 to theiropposite positions, i.e. to the state such that valve 133 is closed `atits input side While valve 132 is open.

It will Ibe noted that the closing of Valve 133 will cut olf pneumaticlluid How from line 137 through the valve, while it will vent thepneumatic pressure in line 138 and beyond. This venting of the pneumaticpressure from line 138 acts to remove pneumatic pressure from thepneumatic actua-tion element 71 `of the fill valve 23 so that themechanical (spring) bias of this valve will act to close same.

At the same time, the pressure that still exists in pneumatic line 136will be transmitted through the now open three way valve 132 to a threeway valve 151 of the double diaphragm actuated valve 110. This three wayvalve 151 stands in its open position by reason of the pneumaticpressure that was applied over the pneumatic line 143 during the timewhen the fill valve 23 was open. Therefore, pneumatic pressure is nowtransmitted via a pneumatic line 152 to the manual valve 106 that is setin its open position. Pneumatic lluid pressure then continues over aline153 to the pneumatic volume tank 1-02 Where a predetermined time delayis introduced.

After the pneumatic pressure has built up in the volume tank 102, itwill be transmitted to the actuator of the relay type Valve 86.Consequently valve 86 will be set to its open condition so as to passpneumatic pressure from the line 83 to the drain diaphragm 91 of thecontrol Valve `90, via the valve structure lof the relay valve 86.Introduction of pneumatic pressure to the diaphragm 91 Will shift thecontrol valve 90 from its preexisting lill position to the oppositestate which may be designated the drain position for the valve. Thisshifting of the control valve to its other position, closes the formerlyopen three way valve 93 and simultaneously opens the three way valve 94.The effect of these valve actions is that the pneumatic lluid pressureis now' cut ol at the valve end of line 87 and is vented from line 126and beyond, by 4the valve 93. At the .same time, pneumatic fluidpressure is now passed on through valve 94 (from pneumatic line 812) tothe pneumatic line 125 and so to a common point 156. Fluid pressure isthus transmitted to a pneumatic line 157 and also to another pneumaticline 158. As `a result of the foregoing, pressure is carried to theinput side of the three Way valve 68, which is at this time in its openposition because the uid in measuring tank 21 is above the oat actuatingmechanism 67 of the valve '63. Consequently, pneumatic pressure istransmitted through valve 68 to another pneumatic line 159 that isconnected to the diaphragm actuator of the single diaphragm valve 115,which is spring biased to a normal state that is opposite to that takenup when pneumatic pressure is applied over the line 159.

This means that a three way Valve 162, of the single diaphragm valve115, will be shifted to its open position and consequently pneumaticpressure will be carried through the valve 162 to a pneumatic line 163that leads directly to the three Way valve 27. Valve 2.7 at this time isin its open position, since the ill valve 23l is closed. Consequentlypneumatic pressure is transmitted over a line 164 to the diaphragm, orpneumatic actuation element 72 of the drain valve 36. This pneumaticlluid pressure will therefore actuate the drain valve 36 to its openposition. The pneumatic control element will then remain in this state(actuated to hold the valve 36 open) during the time necessary for thedraining of measuring tank 21.

It will be observed that there is `an additional pneumatic circuit thatis energized when the three way valve 162 is open. This additionalcircuit includes a pneumatic line 167 that connects to lines 168 and169* in common, This circuit transmits pneumatic pressure to one of thediaphragms of each of valves and 111 in common so that these doublediaphragm valves are set to prepare the system for future action whilelalso providing for the need nection illustrated yfor setting up andcontrolling two con` ditions. One, sothat the fill or drain operationmay not again take place until the succeeding drain or lill,respectively, has been carried out. Thus `for example, pro-l ceedingyfrom the last described operation (where the measuring tank 21 has beenset to drain) it will be noted that the double diaphragm valve 110` willhave a diaphragm 172 thereof actuated, which will close three way v-alve151 and simultaneously vent the pneumatic line 152 4that is connectedthereto. Because of this action, the control valve 90 cannot again beactuated to the drain position, until three Way valve 151 has beenshifted by application of pressure to theyother diaphragm actuatorthereof.

is reached.

The second condition is,v `set up at the same time, be-

cause pneumatic pressure has been applied via line 168 to a diaphragm173 0f double diaphragm `valve 111. This shifts the Ivalve y111 to itsopen position, so that the pneumatic circuit is cleared'lfor admittingpressure to the relay valve 99 that will actuate the control-valve 90 tothe lill position thereof at that time.

The automatic switching back from the drain portion of -a cycle to thenext ll portion, is similar to the switching already described above inconnection with going from fill to drain Thus, it will be clear thatWhen the iiuid has all drained from tank 21, the iloat mechanism inhousing 67 will actuate three way valve v68V to its closed position.This will cut olf pneumatic pressure at line 157 and vent the pressureexisting in line 159. This, in turn, allows the :sing-le diaphragmactuated valve 115 to be returned to its normal, Ior mechanically biasedposition; so that three Way valve 162 thereof will be closed at theupstream side and will vent the downstream side, While another three Wayvalve 176 (of diaphragm valve 115) will be shifted to its openpositionand pneumatic pressure Will be transmitted via -a pneumatic lline `177and through the three Way valve of double diaphragm valve 1111, to thevolume tank 103. At tank 103, the pressure will build upmafter apredetermined delay yand cause actuation of the relay valve 99. Valve 99will, in turn, provide for application of pneumatic pres sure from line80 tothe till diaphragm 92 of the control valve 9G, which shifts thecontrol valve to its lill position. This initiates the lill cycle, ifthe drain valve 36 has completely closed (or las soon as it does), byproviding pneumatic pressure from three Way valve 93 over the line 126,and on over the pneumatic circuit indicated above, which goes to thepneumatic actuator 71 of the vfill valve 23.

4three Way valve y133, which :is open by reason of the concurrent-actuation of single diaphnagm valve 114, to the line 138; land thenthrough the valves 98, 107 and 141 to the three way valve 118 (via lines142, 144 and 1'47). As previously noted, valve 118 is connectedmechanically to drain valve 36. In this manner, las soon las the drainvalve '36 is completely closed, the three Way vallve 118 will be openedland pnessureis then transmittedjover the line 148 to the pneumaticdiaphragm actuator 71 of the ll valve 23. Therefore valve 23 will beopened.

It is pointed out that the counter 9'7 is only actuated for one counteach time that the control valve 90 is shifted to the drain position.Furthermore, -it will not be shifted to the drain position again until'after a lill cycle has been completed, following any given drain cycle.In addition, even though the supply pressure of pneumatic fluid shouldfail during any portion of the tautol@ matic till and drain operation,the system arrangement is such that the control valve 9) will not beshifted until the proper portion of ther actual nlling and drainingoperation In this manner no spurious, or false count indication ofmeasuring dumps will be possible.

It is also pointed out that the counter device 97 has connected theretoak mechanical output arrangement for actuating the valve 981 after lanypredetermined number of dumps has been reached. This is provided so thatthe system will automatically stop after such total number of dumps hasbeen carried out.

Operation of Continuous Fluid Delivery Systemf The operation of thedelivery of fluid from4 the sump tank 3S via pipe 41 to the ultimateconsumer, e.g. to a pipe line; will be clear upon van understanding ofthe various elements involved in the control of the pump 42. However,the operation of this constant delivery system may be briefly reviewedby referring to FIG. l; wherein it lwill be observedA that the pump 42is driven Iat varying speeds by means of the engine 46 that has thespeed thereof controlled by throttle lever 48. The throttle leverposition is controlled in accordance 'with the pressure determined by aconnection from the surge tank, vthat supplies the iiuid to themeasuring tank 21. This pressure -is applied to the diaphragm 47 andactuates the lever arm 49 by moving same about a pivot point 50. This isdone by means of the vlink 51 connecting the arm 49 with the diphragm47. Near the free end of the anni 49 it is connected to act against thespring 54 that tends t0 move the throttle lever y4S to its idleposition. By operating inthe foregoing manner, the capacity of pump 42and the amount of power required to drive same, may be held to a minimumby providing constant flow delivery of the iluid at fa rate that willequal the 'average rate of Huid delivery as it is being measured byintenmittent ow in connection with the iilling and draining of themeasuring tank 21. v Thus, this controlled pumping rate acts to takeinto account the fact that if the head increases on the surge tank, theresulting flow into measuring tank 21 will be increased and thereforethe rate of pump-out `from sump tank 38 should be correspondinglyincreased. This will take place by reason of the increased head pressurecausing la setting of the throttle lever l48 on engine 46 so as toincrease the speed'of drive of the pump 42.

Itis pointed out that the deliverypumping system also includes 5an idleshut down arrangement. This arrangement is such that if the level offluid in sump tank 38 goes below a predetermined height, the floatmechanism in connection with the housing 57 will cause llactuation t .ofthe three Way -valve `58.. yConsequently valve 58 will l to close same.

be opened to allow pneumatic pressure to be transmitted to the diaphragmactuator 63- of the pipe line valve 43 At thesame time it will' causethe opening of 1a bypass circuit from the valve 43 back to the sump tank38, las illustrated..v Also `at the same time, the pneumatic pressurethat is transmitted through the open three way valve 58, will be appliedto the diaphragm I60 so as to actulate the element 59 that Willover-ride the action of the -lever arm 49' (as it is being controlled bythe surge tank head pressure) and will cause the throttle lever 48 ofthe engine 46 to be set to its idle position.

Structure of System Elements -It will be appreciated that many speciiicarrangements and structures for the elements employed in the systemcould be madewith respect to the elements per se that are involved inthe Whole system (schematically shown in FIG. l). However, by Way ofillustration-and in order to be sure that the entire system operation isclear, a particular layout of one set of elements has been illustnatedin the remaining figures of the drawings.

Thus FIGS. 2, 3 and 4 illustrate the elements that are contained on acontrol panel which elements have 1 1 been enclosed by a dashed line(180) in FIG. 1. Whereever possible, the same reference numerals areemployed, to indicate the various valves and other elements of thecontrol system as it is illustrated in FIGS. 2, 3 and 4, as wereemployed in the schematic diagram of FIG. 1.

As with most of the elements per se of the pneumatic control system, thecounter actuated three way valve 93 may take various forms; and theillustrated embodiment is merely shown by way of illustration of oneparticular type of valve that may be employed. Thus, the valve that ispreferably employed for valve 98 is that illustrated in FIG. 5. This isa pneumatic, relay or pilotvalve actuated, type of valve that has anactuating arm 183. Arm 183` is moved by a plunger 184 in a pivotalmanner. Plunger 184 is connected adjustably to the counter 97 in such away that the plunger -is moved longitudinally (downward, as viewed inthe illustrations) when a predetermined number of dump counts have beenmade. -It will be appreciated that the particular structure, inconnection with the counter elements of counter `97, that actuates theplunger 184 is not material to this invention so that any desiredstructure (not shown) may be employed.

The structure of the actuator that moves plunger 184 is such that beforethe predetermined number of dumps has been reached, the plunger will bein its upward position so as to hold the arm 1183 raised, ina generallypivotal manner, about its spring supported end (clearly illustrated).Such raising of arm 183 allows a pilot valve core 186 to be lifted offits lower end valve seat, and

thus allows pneumatic -iluid under pressure to flow via the illustratedpassages into a chamber 1187 on the left hand side (as viewed in FIG. 5)of a diaphragm 188 of the valve 98. Consequently, so long as thepredetermined count has not been reached, the pneumatic uid pressure asit exists in an input tube 189 will flow through a passage 191i and pastthe valve core 186 by unseating same. At the same time this pneumaticfluid pressure will hold the valve core 186 up so that the valve at thetop of the core is closed, and so that pressure is transmitted intochamber 187. This pressure will cause the diaphragm 188 to be liexed andthus displace a rnain valve spool 193 to the'right (as viewed in FIG.5). This will open the valve at the right hand end (as viewed in FIG. 5)of spool 193, while closing the other valve on the left hand endthereof.This means that pneumatic uid may now liow from the inlet ytube 189directly past the right hand end valve, of spool 1931, and out throughan outlet passage 194. At the same time, the closing of the left handvalve in connection with spool 193 will cut oifthe free passageway forpneumatic fluid flow that othenwise exists between the outlet passage194 and a vent passage 195.

It will be observed that the hub of the valve spool 193 is made with anecked down central portion that joins two guide shafts 196 forpermitting longitudinal sliding movements of the spool. These guideshaft portions 196 of the hub are square in cross section so that thereis free passageway for flow of pneumatic fluid between either the outletpassage 194 and vent 195, or in the other direction between outletpassage 194- and the inlet tube 189. Which of these directions of iluidflow will be open, depends upon the position of valve spool 193 that hasconical surfaces at the ends thereof that match valve seats at the endsof the circular cross section passage that carries the hub of spool 193therein.

FIGS. y6, 7, 8 and 9 show some of the structural deltails of the drainvalve 36 that is illustrated schematically in the system shown inFIG. 1. These details include the mechanically actuated three Wayinterlock pneumatic valve 118 that is controlled by the actuatingmechfamism of valve 36 so that'iwhen the valve 36Vis in its n fullyclosed position, the pneumatic valve 118 will be opened. Valve 36 itselfmay be a commercially available type, such as one manufactured byKeystone that is a buttery construction, and that is actuated by meansthat include a rack and pinion connection which is illustrated in FIG.8. The actuating structure is arranged so that the valve is springbiased to its closed position. The actuator 72 that is schematicallyillustrated in FIG. l is preferably a pneurnatically .controlleddiaphragm type actuator `as indicated in FIG. 6. VOne such actuator thatis commercially available is manufactured by Fisher.

The actuator 72 has an output shaft 197 that is connected to a rack 1913(FIG. 8) of the rack and pinion mechanism that actuates the butterflyvalve structure of valve 36. Connected to the shaft 197 and movedthereby, is an arm 201 (FIGS.y `6 and 7) that extends transversely fromthe sha-ft 197 and has an adjustable bolt 282 near the free end thereoffor making Contact With a handle or knob 201) of the pneumatic valve118.

Valve 118 isa conventional, three way valve that has internal structurein accordance with the showing of FIG. 9 for providing -valveconnections. There is an inlet port 283 that may be connected witheither one of two outlet ports 204 or 2815, in the alternative. Thevalve is provided with a spring .286 to bias it into the closed position(insofar as the way in which it is used in the pneumatic control systemof FIG. 1). Thus, as used in the systern illustrated in FIG. l, Wherethe valve 118 is schematically indicated, the pneumatic line 147 will beconnected to the port 285 While the line 148 -will be connected to port293. In this manner it will vent the pneumatic line 148, via port 264when it is in the closed position; while it will connect the pneumaticlines 147 and 148 to one another when it is in its open position.

The adjustment of the bolt 202 will be set so that valve 1118 will notbe actuated to its open position until the drain valve 36 is fullyclosed, i.e., when the actuating shaft 197 is in its full-up position.

It -will be :appreciated that the other pneumatic interlock Valve 27(that is connected for mechanical actu-ation by the fill valve 23) maybe essentially the same as the valve 118 that is shown in FIGS. 6, 7 and9. Similarly, it will be clear-that the till valve 23 is substantiallylike the drain vvalve 36 including the pneumatic actuator therefor. Theonly differences would be those involved in mounting valve 23 in ahorizontally situated pipe line as opposed to the situation of valve 36in a vertical `section of piping.

l`The float yactuated valves may take various forms, `and the particulartype of such valve that is employed, forms no part per se of theinvention. However, `a particular type of relay actuated valve may bethat illustrated in FIG. l0. Thus, referring to FIG. l0, there is apilotvalve core 289 that is actuated by a oat controlled arm 210. Theaction of this valve is such that when the fluid is below the level ofthe oat, the arm 218 is hel-d up by pivoting action from the float whichis then in its downward position. 'Thus the core 209 is lifted and thevalve at the -free (lower) end thereof is opened, while the valve at theattached (upper) end :is closed. This means that the pneumatic fluidpressure that is applied at a passage 212 can flow via la crosspassageway'213, and then past the valve at the free end of core 289, toilow on through a passage 214 to 4a chamber 215 where a diaphragm 216will be exed by the pressure applied and will cause the main walvestructure to be moved over to theposition illustrated in FIG. 10. Thisthen opens the main valve passageway through from the passage 212 to apassage 217 via the hexagonalshaped body of the main vialve spoolstructure.

When the fluid level acts to lift the float, the arm 218 will bedepressed and the core 289 will he correspondingly pushed downward whichwill seat the valve at the free end thereof and close same. This willcause the other valve (at the upper end of core 209) to be opened vandvent the chamber 215. Consequently the main valve spool will Abe free tomove to the left. This allows the FIG. 3. It is'pointed out that thestructure of this valve is conventional, and willbe clear to lanyoneskilled inthe art upon an inspection of the FIG. ll illustration whichshows the interior elements by means of a longitudinal cross-sectionbreak away. Y y

It'will be observed that in actual structure this valve is a four-waytype of valve. Howevenxthe loperation is just as vitvvas described inconnection with FIG. l, by

reason of the .fact that a common connection lfor the pneumatic lines 87.and 820i the FIG. l diagram is used. In other words the pneumatic lines82 `and 37 (FIG. 1)

are actually only one single pneumatic tube that is connected to `aninput port 2250i the actual valve structure for valve M that is shown inFIG. l1. lThere are two outlet ports 22o and 227 that are alternativelyconnected directly to the inlet port 22S. At the sarne time the other ofthese two outlet ports is vented to the atmosphere, by means of theopening existing aro-und the valve core 23@ (double spool shape) thatleads out the corresponding end of a -valve body or housing 231 of thevalve 90.

It is to be notedthat the valve core 230 is moved longitudinally toeither extreme position, by means of a pair of diaphragm's `and 92, thattarel schematically indicated in the FIG. l system showing. Theoperationof the valve is such that either .of the two positions taken upby the valve co-re, tend to remain in such position thereafter eventhough the pressure is removed, -until another pressure signal isyapplied to the other of the actuating diaphragrns 91 or :92. In otherWords it -will be. noted that there is no bias force on the valve core230, audit will therefore remain in any given position` until shifted bythe application of pneumatic pressure-to the retracted one of theactuating diaphragrns 91 or 92; Thus, when pneumatic pressure isintroduced via la port l23e to cause diaphragm 92 to be expanded; thevcore 230 of the` valve will be shifted to its opposite position (fromthat illustrated in FIG. l1) and consequently the inlet port 225 will bedirectly connectedonly to the outlet port 227. Also, the otheroutlet'port 2.26 will then be vented, lby having -a free passageway tothe atmosphere past the seal yat its end of the valve housing231. Thelatter ifs so because the left hand reduced diameter portion of the core230, will thenbe shifted to lie opposite the outer seal at that end. Thecore 23d and attached element will remain in this position, even afterthe pneumatic pressure that was-applied at port 234 has 'been removed.Of course, the opposite action takes place when pneumatic pressune isapplied to the diaphragm 91,

via a 'corresponding port 235 at the other e-nd of the valve structure.4

FIG. `12 illustrates the structure of `a valve that may be employed aseither of the two relay-type valves 86 or 99 in the illustrated system.this valve has a diaphnag-m actuating port 238 for int-roducingpneumatic pressure that will act on a diaphragm 239, to lift sameagainst the pressure of -a coil spring 240x This action positions athreey way valve that is clearly illustrated, and that has an inlet port243 which is either It will be observed that biased type valves 114i and115 of the illustrated system.

lt'will be observed that there is a spring 248y that biases the valve toone extreme position inthe absence `of any pneumatic pres-sure appliedtothe diaphragm. he arrangement is such that the pneumatic pressurewhenapplied to la port 249, will overconte'the pressure of spring 24S andmove the valve to its opposite extreme position, as indicated in FIG. 13by the dashed Iline showing of lthe opposite (rtree) end of the valvecore. t It is pointed out that the internal valve structure i'or thisvalve lis substantially the same as the internal valve structureillustrated in FIG. 1l.v Thus, the valve shown in FIG. 13 is also afour-way valve that will connect an inlet port 250 alternatively toeither one of a pair of outlet ports 251 or 252, while the outlet portthat isnot thus connected with inlet port 250, vented, or connected 4tothe atmosphere as was indicated with theinternal valve structure of theFIG. ll valve.` i

Y FIG. 14 illustrates the structure for a three way, double diaphragmactuated valve that may be ,used as the valve 11'@ or 111 of theillustrated system. The structure is similar to the other valvesillustrated, so that it is deemed sulicient to point out that there isan'inlet port 255k` that is either `closed or is connected to an outletport 256. When outlet port 256 is not connected to inlet port 255, it isvented by means of being connected for free' flow through the rightliand end of -a body or housing' 257 of the valve. n' y It will beobserved'that the valve illustnated in FIG. 14 is not spring biased to'any igivenposition, but will be actuated to either of itsextremepositions by means of f o ne or the other of thetwodiaphragms'that are connected for moving the core (or spool) of thevalve back and forth. `In other words this valve, like the control valve9i? :that was specifically illustrated in FIG. 1l, will be actuated toone or the Vother of its two Ipositions by having pneumatic pressureapplied to a given one of the diaphragms thereof. Thereafter the valvecore will remain in that position, `even after the removal of. pneumaticpressure on the actuating diaphragm, until the pneumatic pressure hasvbeen applied to the otherA diaphragm so as to move thelcore back .toits lirst position again. l

FIG. 15 illustrates the structure for a manually actuated, three wayva'lve that may be the valve Ai136 or'107 in the illustrated system.Here again, vthe valve structure is quite similar to other valvesdescribed fand illustrated above, 'and it is deemed merely necessary topoint shut oft or connected to an outlet port 244; depending upper valvestructure `and so connects outlet port 244 with a port 245 which is leftopen as a vent. No further outthat this three Way valve operates toconnect a port 260 to either of two other ports 261 or 262 in thealterna- When the valve is used Iin accordance with the system of thisinvention, the port 261 is used .as `the inlet :port so that it iseither connected to port 26o `(when the valve li-s open) or it isclosed. On the other hand, the

port 260 (which is an outlet port) is either connected.

to inletport 261 or it is connected to the other port 262 which will helett open las `a vent. y

While va preferred embodiment of the invention has been described inconsiderable detail, in accordance with the applicable statutes, this isnot to be taken jas in any waylirniting the invention but merely asbeing descriptive thereof. ,L

What is claimed las the invention is:

1. A pneumatic control system for `automatic custody transfer of fluidscomprising in combination a lknow/n volume measuring tank, a fill valvelfor `controlling the introduction of iluid to said measuring tank, a:drain'valve for controlling the removal of iiuid from ysaid measuringtank, pneumatic control means fior actuating each of said ll 'and drainvalves, a iirst pneumatic valve, lirst fluid level responsive means atthe full level of said measuring tank, 1a second pneumatic valve, secondfluid level responsive means at the `iempty level :of said measuringtank, means viior actuating said rst pneumatic valve in response to saidiirst fluid level responsive means, means for lactuating said secondpneumatic valve Iin response to said second uid level responsive means,a third pneumatic valve actuated by said lill valve when in the closedposition, a fourth pneumatic valve actuated by said drain valve wlhen inthe closed position, a pneumatic control valve having two positions,pneumatic circuit means for connecting ia source :of pneumatic pressureto said control valve, a fifth pneumatic valve having a pneumaticactuator theireor, a sixth pneumatic valve having a pneumatic actuatortherefor, additional pneumatic circuit means for connecting said controlvalve to each of said fifth and said sixth pneumatic valves foractuation thereof alternatively, said `additional pneumatic circuitsincluding a connection to teach of said pneumatic actuators via said rstand second pneumatic valves respectively, pneumatic circuit connectionstE-rom said control valve via said fth and sixth pneumatic valves andvia said third and `fourth pneumatic valves in series with eachrespectively for carrying pressure lto :said lill and drain valvepneumatic control means in the alternative, with interlock created bysaid third and Afourth valves, and counting means connected to saidcontrol valve for indicating the number of times it is in the positionfor connecting pneumatic pressure to open said drain valve and deliver atank of iluid.

2. A pneumatic control system for automatic custody transfer of fluids,comprising in combination a known volume measuring tank, a till valvefor controlling the introduction of uid to said measuring tank, a drainvalve for controlling the removal of iluid iront said measuring tank,pneumatic control means lfor actuating each kof said lill and drainvalves, means tor supplying pneumatic pressure to the system, a rstpneumatic valve, first lluid level responsive means at the full level ofsaid measuring tank, a second pneumatic valve, second uid levelresponsive means at the -empty level of said measuring tank, means rl'orlactuating said first pneumatic valve in response to said first liuidlevel responsive means, means for actuating said second pneumatic valvein response to said second iluid level responsive means, a pneumaticcontrol valve for alternatively controlling the application of pressureto said pneumatic control means for each of said ll and drain valves,first pneumatic circuit means for connecting said iirst and said secondpneumatic valves to said pressure supply means -in order to switch saidpneumatic control valve, and second pneumatic circuit means including lathird pneumatic valve actuated by said lill valve when in closedposition and a fourth pneumatic valve actuated by said drain valve whenin closed position,

second pneumatic circuit means comprising a series connection Ifrom saidsupply means to each of said pneumatic control means via the other oneof said third and fourth pneumatic valves to provide `an interlock toprevent simulvolume measuring tank, a lill valve for controlling theintroduction of fluid to said measuring tank, a drain valve forcontrolling the removal ot fluid from said measuring tank, pneumaticcontrol means 'for actuating cach of said lill and drain valves, meansfor supplying pneumatic pressure to the system, a irst pneumatic valve,iirst lluid level responsive means at :the full level of said Imeasuringtank,

a second pneumatic valve, second fluid level responsive -drai'n valves,iirst pneumatic circuit means for connecting said rst land said secondpneumatic valves to said pressure supply means in order to switch saidpneumatic control valve, a third pneumatic valve actuated by said illvalve when in closed position, a`fourth pneumatic valve actuated Ibysaid drain valve lwhen in .closed position, a `second pneumatic circuitmeans for connecting said control valve to the drain one lof saidcontrol means Iand having said third pneumatic valve in series therein,and a third pneumatic circuit means -for connecting said control valveto the lill one of said contro-l means and having said fourth pneumaticvalve Iin series therein, said `second and third pneumatic circuit meansproviding yan interlock to prevent opening of either said ll or drainvalves when the other is open.

5. A pneumatic control lsystem for automatic custody trans-fer of fluidsaccording to claim 2 further including a sump `for receiving luiddrained `from said measuring tank, a purnp for delivering said iluidlfrom said sump after measurement thereof, a variable speed engine fordriving said pump at a steady rate equal to the average flow of saidmeasured fluid, pressure responsive means for adjusting the speed ofsaid engine, and means for introducing pressure to said last named meansin accordance w-ith the head on said principal supply source. K 6. Anautomatic custody transfer system according to claim 5 including athrottle for controlling the speed of said engine, pressure responsivemeans for .adjusting the setting of said throttle, means yforintroducing pressure to said last pressure responsive means inaccordance with the head on said principal 4supply source, third fluidlevel responsive means in said sump', a iiuid by-pass path yfrom theoutput side of'said pump to said sump including -a fifth valve in the-output stream for diverting the liow to the bypass path,A secondpneumatic circuit means including said third fluid level responsivemeans 4and means to actuate said fifth valve, and override means forlsetting said throttle to the idle position, all ffor idling said engineand recirculating said `iiuid if the level in the sump goes below apredetermined level.

References Cited in the file of this patent UNITED STATES PATENTS

1. A PNEUMATIC CONTROL SYSTEM FOR AUTOMATIC CUSTODY TRANSFER OF FLUIDSCOMPRISING IN COMBINATION A KNOWN VOLUME MEASURING TANK, A FILL VALVEFOR CONTROLLING THE INTRODUCTION OF FLUID TO SAID MEASURING TANK, ADRAIN VALVE FOR CONTROLLING THE REMOVAL OF FLUID FROM SAID MEASURINGTANK, PNEUMATIC CONTROL MEANS FOR ACTUATING EACH OF SAID FILL AND DRAINVALVES, A FIRST PNEUMATIC VALVE, FIRST FLUID LEVEL RESPONSIVE MEANS ATTHE FULL LEVEL OF SAID MEASURING TANK, A SECOND PNEUMATIC VALVE, SECONDFLUID LEVEL RESPONSIVE MEANS AT THE EMPTY LEVEL OF SAID MEASURING TANK,MEANS FOR ACTUATING SAID FIRST PNEUMATIC VALVE IN RESPONSE TO SAID FIRSTFLUID LEVEL RESPONSIVE MEANS, MEANS FOR ACTUATING SAID SECOND PNEUMATICVALVE IN RESPONSE TO SAID SECOND FLUID LEVEL RESPONSIVE MEANS, A THIRDPNEUMATIC VALVE ACTUATED BY SAID FILL VALVE WHEN IN THE CLOSED POSITION,A FOURTH PNEUMATIC VALVE ACTUATED BY SAID DRAIN VALVE WHEN IN THE CLOSEDPOSITION, A PNEUMATIC CONTROL VALVE HAVING TWO POSITIONS, PNEUMATICCIRCUIT MEANS FOR CONNECTING A SOURCE OF PNEUMATIC PRESSURE TO SAIDCONTROL VALVE, A FIFTH PNEUMATIC VALVE HAVING A PNEUMATIC ACTUATORTHEREFOR, A SIXTH PNEUMATIC VALVE HAVING A PNEUMATIC ACTUATOR THEREFOR,ADDITIONAL PNEUMATIC CIRCUIT MEANS FOR CONNECTING SAID CONTROL VALVE TOEACH OF SAID FIFTH AND SAID SIXTH PNEUMATIC VALVES FOR ACTUATION THERE-